The present embodiments relate to an arrangement for an X-ray image system with a grid frame arranged to enable the grid fame to oscillate.
Known X-ray equipment for fluoroscopy of an object for examination has an X-ray source for the generation of X-rays that pass through the object to be X-rayed. The X-rays are recorded by an image recording device. The image recording device may be imaging cartridges for X-ray films, storage film cartridges, or X-ray image detectors for digital image recording. The image recording device is to be positioned in the X-ray beam generated by the X-ray source for this purpose. Positioning takes place by a pullout drawer, into which the image recording device is inserted and entered into a drawer housing which, for example, is integrated into a patient table of the X-ray device. There may be an automatic exposure chamber (e.g., an iontomat chamber) in the patient table above the drawer housing.
A known problem, for example, when X-raying objects for examination involving greater thickness, is scattered radiation. The scattered radiation may be formed by deflection of the examination rays in the X-rayed object for examination. An anti-scatter grid that is inserted into a grid frame above the automatic exposure chamber may be used to reduce the scattered radiation on the image recording device. For the most part, the anti-scatter grid may be removed, as X-ray images are in part taken using an anti-scatter grid with variable focus and different aspect ratios, or also in part without any anti-scatter grid.
It is known that the use of anti-scatter grids may result in distorting stripes or grids on the diagnostic image recorded in the detector. To reduce or eliminate these distorting stripes, the grid frame may be oscillated during the examination. For good image quality, the X-ray emission is to be triggered in the middle of an oscillation period of the oscillating grid frame. In known X-ray equipment, the grid frame passes through a switch, via which the time at which the X-ray emission is triggered is controlled. After expiry of a defined time (e.g., a derivative time), emission is triggered after passing through the switch. It is a proven principle to generate the oscillating grid movement by a grid frame suspended on springs. In doing so, the grid frame is preloaded with an actuator. In order to trigger the oscillating vibration, the grid frame is decoupled from the actuator. The mode of vibration results from the spring rate, the oscillating weight and the preload path. A disadvantage of this principle is that for different weights of the anti-scatter grids, different oscillation periods are set. However, as the derivative time is always the same, with anti-scatter grids of different weights, the X-ray emission may therefore not be constantly triggered in precisely the middle of an oscillation period of the oscillating grid frame.
When creating an image recording without using an anti-scatter grid, oscillation of the grid frame is to be avoided wherever possible, as these oscillations may result in image blurring. In known solutions, an additional switch is used to detect whether an anti-scatter grid is inserted in the grid frame.